I got Bruce about 1.5 weeks ago and after about 7 days of having him he began to bite his tail. I know it is tail biting because there is no color at the tips and his tail went from completely fine one morning to completely shredded that same night.

Bruce is in a 3.5 gallon with a filter (Aqueon Evolve4). The filter output is quite strong so I have both the input and output completely covered with filter media. This has helped immensely and now he has a very weak current. I also drilled some holes in the filter tube to make it even less.
He has plenty of hiding spaces in the tank. Two anubias plants, a temple ornament (with hiding space), and a soft grass-like plastic plant. I also have half of an indian almond leaf in there. It's been in there for about two days now.
For his boredom, I tried giving him a ping-pong ball to float in the tank but he seems to pay no attention to it. He responded well to me putting a picture frame with photo next to the tank. He likes to look at it but this has not kept him from biting his fins.

I have been doing 50% water changes every other day and adding stress coat for every water change. I can't tell at the moment whether it's getting worse every day but for now, I can't really tell a significant change since I started doing the water changes/stress coat.

Is there anything else I could try to make sure that this doesn't happen again? Am I doing anything wrong? :( I'm afraid he's going to end up making it worse and possibly get fin rot.
thanks!

I thought my filter was really slow it was only a trickle and no current in the tank at all. it was just a little trickle of water falling into the tank. My fish still protested by biting his tail.

Since I took the filter out all together he has stop and his tail is growing in. He no has no filter at all I did put a little bit of ammo chips for help if ammonia becomes a problem if I slack off on his water change.

I thought my filter was really slow it was only a trickle and no current in the tank at all. it was just a little trickle of water falling into the tank. My fish still protested by biting his tail.

Since I took the filter out all together he has stop and his tail is growing in. He no has no filter at all I did put a little bit of ammo chips for help if ammonia becomes a problem if I slack off on his water change.

Thanks for the advice snowflake. It might be the filter that's doing it since he was in a pet store cup for a good two weeks & did nothing bad to his tail. :( I will monitor his tail biting for a few days and if it gets worse, I'm unplugging the filter.

Thanks for the advice snowflake. It might be the filter that's doing it since he was in a pet store cup for a good two weeks & did nothing bad to his tail. :( I will monitor his tail biting for a few days and if it gets worse, I'm unplugging the filter.

Mine was the same. Looked good in the cup. A few days with a filter and he was not happy.

Tail biting is a major reason I'm done breeding and keeping long finned fish.

You can try removing the filter if he doesn't stop. You can also try a bigger tank, more or less decorations, a higher or lower traffic area of your house, a higher or lower temperature, letting him flare for ten minutes a day, etc... In the end, he could just tail bite for life and you may not be able to stop it. In that case, keep his water clean and warm and watch for infection.

Just FYI, tail-biting doesn't usually give a shredded appearance. It tends to look more like small chunks being taken out -- betta mouth-sized chunks. Shredding is more likely from snagging on an object in the tank (and some bettas can snag on things as benign as the adjustment knob of their heater), or from fin rot or ammonia burns.

Tail biting is a major reason I'm done breeding and keeping long finned fish.

You can try removing the filter if he doesn't stop. You can also try a bigger tank, more or less decorations, a higher or lower traffic area of your house, a higher or lower temperature, letting him flare for ten minutes a day, etc... In the end, he could just tail bite for life and you may not be able to stop it. In that case, keep his water clean and warm and watch for infection.

I can see why people prefer short finned bettas! They're less of a headache. haha. I will definitely monitor him well to see if it's getting worse and play around with the tank a bit more. I'm hoping he grows out of it. I miss his beautiful full tail!

Just FYI, tail-biting doesn't usually give a shredded appearance. It tends to look more like small chunks being taken out -- betta mouth-sized chunks. Shredding is more likely from snagging on an object in the tank (and some bettas can snag on things as benign as the adjustment knob of their heater), or from fin rot or ammonia burns.

Clean water and maybe some StressCoat+ would be a good idea.

It's definitely bite chunks. I guess the shredded look is subjective? haha. There aren't holes or anything just chunks missing from the end of the tail. I did the panty hose trick on all of the plants I have and it passed so I don't think it's anything inside the tank that's hurting him. So far, no infection either. So I'm crossing my fingers here!